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Re: Structural support, was: oil dielectric

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

>>Absolutely! And a glazed surface would be preferable to reduce
>>absorption of potentially conductive material. Ceramic has been used for
>>high power RF coil forms for almost 100 years. The downside to using
>>ceramic is that it's significantly heavier and more brittle than PVC. 

> You are correct about the ceramics being much heavier and more brittle. I
> questions about useing 300 series  (non-magnetic) stainless in another
> post.This would allow for a thinner coating of ceramic. Reply posts indicate
> metals would absorbe energy in the form of heat causeing losses in the
coil, as
> well as expansion and contraction in the steel tube. I would not see any
> problem with using pvc coated with ceramic

	Why coat the PVC with ceramic?
	What benefit or purpose is obtained?
	As many have pointed out (and demonstrated) PVC (or HDPE) is
	fine, as is, as a form/support.

	When dealing with 10s of KW of RF, in the vicinity
	of hot tubes, Ceramics have a place.  Or did.  Ceramics
	were used when HDPE (etc) did not exist.

> in place of the stainless, except that the glazeing process would

> melt the pvc. Just how hot would a piece of iron become inside a

> ceramic tube?

	Essentially all the power in the coil would end up there.
	None left for sparks (or whatever...)

> Envision for a moment, two stainless or titanimum tubes, separated

> by a ceramic spacer for the central body of the coil.

	The form?

	The stainless would absorb all the power of the coil.

> Would stainless steel heat less?

	Than what?
	Stainless, or any conductor, will absorb essentially
	all the power.

> Although stainless and  titanimum might heat inside a Tesla coil,

> if thinner pieces were used, would they heat less,

	Depends on the shape, whether there are slits, (to block
	circulating currents), etc.

	Why would Stainless be put in the form?